why not?

src/cmd/p.c

@@ -0,0 +1,90 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+#define	DEF	22	/* lines in chunk: 3*DEF == 66, #lines per nroff page */
+
+Biobuf *cons;
+Biobuf bout;
+
+int pglen = DEF;
+
+void printfile(int);
+
+void
+main(int argc, char *argv[])
+{
+	int n;
+	int f;
+
+	if((cons = Bopen("/dev/cons", OREAD)) == 0) {
+		fprint(2, "p: can't open /dev/cons\n");
+		exits("missing /dev/cons");
+	}
+	Binit(&bout, 1, OWRITE);
+	n = 0;
+	while(argc > 1) {
+		--argc; argv++;
+		if(*argv[0] == '-'){
+			pglen = atoi(&argv[0][1]);
+			if(pglen <= 0)
+				pglen = DEF;
+		} else {
+			n++;
+			f = open(argv[0], OREAD);
+			if(f < 0){
+				fprint(2, "p: can't open %s\n", argv[0]);
+				continue;
+			}
+			printfile(f);
+			close(f);
+		}
+	}
+	if(n == 0)
+		printfile(0);
+	exits(0);
+}
+
+void
+printfile(int f)
+{
+	int i, j, n;
+	char *s, *cmd;
+	Biobuf *b;
+
+	b = malloc(sizeof(Biobuf));
+	Binit(b, f, OREAD);
+	for(;;){
+		for(i=1; i <= pglen; i++) {
+			s = Brdline(b, '\n');
+			if(s == 0){
+				n = Blinelen(b);
+				if(n > 0)	/* line too long for Brdline */
+					for(j=0; j<n; j++)
+						Bputc(&bout, Bgetc(b));
+				else{		/* true EOF */
+					free(b);
+					return;
+				}
+			}else{
+				Bwrite(&bout, s, Blinelen(b)-1);
+				if(i < pglen)
+					Bwrite(&bout, "\n", 1);
+			}
+		}
+		Bflush(&bout);
+	    getcmd:
+		cmd = Brdline(cons, '\n');
+		if(cmd == 0 || *cmd == 'q')
+			exits(0);
+		cmd[Blinelen(cons)-1] = 0;
+		if(*cmd == '!'){
+			if(fork() == 0){
+				dup(Bfildes(cons), 0);
+				execl("/bin/rc", "rc", "-c", cmd+1, 0);
+			}
+			waitpid();
+			goto getcmd;
+		}
+	}
+}